Lubricating of leather



Patented Oct. 17, 1939 UNITED STATES LUBRICATING F LEATHER Joseph GeorgeNiedercorn, Riverside, Conn, as-

signor to American Cyanamid Company, New York, N. Y., a corporation ofMaine No Drawing. Application September 7, 1938, Serial No. 228,762

3 Claims.

This invention relates to the fatliquoring and stufilng of leather, andmore particularly to the use of new classes of lubricants for thispurpose. The invention includes the lubricants themselves,

5 processes wherein they are applied to the leather and lubricated skinsand leather containing them.

The lubrication of leather with fats, oils and similar materials hasbeen practiced for many years on both vegetable tanned and mineraltanned leather. Heavier leathers such as sole leather, belting leatherand the like are frequently impregnated with oils and fats, which areusually applied assuch or dissolved in an organic solvent such 'asnaphtha. This method of application is usually referred to as stufling",burning in or "oiling off and is characterized by the fact that thelubricant is applied to the leather either without any solvent at all orin a 20 non-aqueous medium such as an organic solvent. It is customaryto use raw oils and fats in this type of leather finishing.

Another standard method of leather lubrication is known as fatliquoring.This method is more frequently applied to splits and other cheapergrades of upper shoe leather as well as to the finer grades of lightleather such as calf skins and kid skins. It is distinguished from thestufling processes referred to above by the fact that the skins orleather are treated with oils, fats or other lubricants in the form ofan aqueous emulsion, usually by agitation in a rotating drum, and it iscustomary to employ at least a substantial quantity of the lubricant insuitenated form. It is therefore proper to distinguish between stuiflngand fatliouoring processes both by the method of applying the lubricantto the leather and by the fact that in one case the lubricant isunsulfonated while in the other case it is usually employed in at leasta partially sulfonated form.

Satisfactory lubricating compositions for stun.- ing and fatliquoringprocesses must possess certain characteristics not found in all oils andfats.

5 A satisfactory lubricating agent for this purpose should be stable andnot subject to rancidity, and should be capable of ready absorption bythe leather without leaving a greasy surface. A further requirement,which is particularly important in lubricants for light-colored leatherssuch as white glove leather, chrome tanned upper leather and the like isthat the oil should possess and retain a light color during the expectedlife of the leather.

Sperm oil is one of the most satisfactory of the large number oflubricants that have previously been used for stuffing and fatliquoringleather. This oil is stable and possesses a fairly light color in rawand sulfonated form, and its greatest objection has been its pronouncedfishy odor.

Unfortunately the supply of sperm oil is rapidly diminishing for thesperm whale, from which it is obtained, is rapidly becoming extinct. Forthis reason there is an increasing demand among leather finishers for asatisfactory substitute for both raw and sulfonated sperm oil.

I have found that the oil expressed from the seeds or nut kernels of thejojoba bush is an excellent leather lubricant, both in its raw state andafter sulfonation, and that its lubricating characteristics for leatherresemble those of sperm oil very closely. The jojoba bush is a shrubwhich is found in the more arid parts of Arizona, Mexico and southernCalifornia. It reaches maturity in about two years, can be readilycultivated on land that will support few other plants and producesseveral crops of seeds a year, depending on the rainfall. Accordingly,the supply of oil obtainable from the seeds of this plant is unlimited,whereas the available supply of sperm oil is rapidly diminishing. Forthis reason, I regard the raw and sulfonated jojoba seed oils as beingof great potential importance to the leather industry, for they providean improved substitute for classes of leather finishing materials thatare becoming increasingly diiilcult to obtain.

I have found that both raw and sulfonated jojoba seed oil can be appliedto skins and leather by any of the methods of impregnation used byleather fin shers, including the methods known as stufling andfatliquoring. The raw oil is quite similar to sperm oil in its physicaland chemical characteristics but it is lighter in color and possessesnone of the fishy odor that is so characteristic of the sperm oil. Thefollowing table sets forth the more important physical and chemicalcharacteristics of this oil, and the corresponding figures for sperm oilhave been inserted for purposes of comparison.

Joiobs seed oil Sperm on Refractive index at 25 C l. 4648 l. 4573Specific ravity 25l25 0.8642 0.8799 Iodine value 81.7 81-90Snponiflcatiou value 92. 2 x25. 2-1326 Uusaponiliablc matter 4B. 3 37-4!Acctyl value of uusaponifiahle matter 17L 8 161-190 iodine value ofunsaponif'mhle matter 77, 2 65 iodine value of fatty acids. 76.1 83.2-85. 6 Neutralization value of fatty acids. W2. 0 190-199 Consolationtemperature, "C 10-12 5 to lo lycerol, percent o. 0 0. 0-5. 5 Saturatedacids, percent l. 64 i0. 0

From the above table it will be seen that jojoba seed oil can be easilydistinguished from sperm oil. It differs from the latter by its higherspecific gravity, higher content of unsaponifiable matter and lowercontent of saturated fatty acids. It contains no glycerides, although inthis respect it probably does not differ from some sperm oils. The fattyacids of jojoba seed oil have longer carbon chains than those of spermoil, as may be seen from their respective neutralization values. Theiodine value of these fatty acids is lower than those of sperm oils, butthe iodine value of the unsaponifiables is higher.

The raw jojoba seed oil is especially well adapted for use in stufiingprocesses, either as such or in admixture with heavier oils or greasessuch as Moellon Degras, olein and the like. The oil may be impregnatedinto the leather in a rotary drum as in drum stufiing, or it may berubbed into the surface of the leather as in hand stuffing or "oilingoff". In either case a soft and well lubricated piece of leather isobtained.

The sulfonation of jojoba seed oil presents no serious technicaldifliculties, for I have found that the sulfonated oil can be easilyprepared by the ordinary methods of sulfonation. Sulfonated joboba seedoil is a clear yellowish-white oil at 40 C. which slowly settles outfine particles of waxy material upon standing at room temperatures. Thischaracteristic is extremely important in fatliquoring and stuffingleather, for the finely divided waxy particles serve to give skins andleather treated with this oil a softer surface than those treated withother fatliquoring agents. During the fatliquoring or stufilng processthe waxy particles are apparently lodged in the surface of the leatheror skin and give it a characteristic emollient or unctuous feel thatcannot be duplicated by any other leather lubricant of which I am aware.For this reason the present invention is especially well suited forfinishing glove leather, doeskins for jackets, and other leather wearingapparel that is worn in contact with the human skin.

The sulfonated jojoba seed oil may be used in the preparation ofstufling compositions, but it is especially well adapted for use infatliquoring. I have found that the oil is easily emulsified with water,either with or without the addition of emulsifying agents, and that goodexhaustion of the fatliquoring bath is easily obtained. Preferably sucha fatliquoring bath contains from 5-15% of the sulfonated oil, based onthe weight of the leather, together with fill-300% of water. of course,the amounts of oil and water can be varied through a much wider range infatliquoring leathers of different characteristics, and it should beunderstood that the invention in its broader aspects is not limited toany specific concentrations or ratios of sulfonated oil to leather.

The advantages of the present invention can also be obtained, at leastin part, when sulfonated jojoba seed oil is used as a stuifing orfatliquoring agent in admixture with other lubricating materials. Forexample, it is quite evident that sulfonated sperm oil can be used as adiluent for sulfonated jojoba seed oil in fatliquoring processes ifdesired. It is also possible, of course, to employ the sulfonated jojobaseed oil as an emulsifying agent in fatliquoring baths or in stuifingcompositions which also contain unsulfonated fats, oils and the like,such as are frequently employed in lubricating calf leather, chrometanned upper leather and other heavier leathers. These and similarfields of application will readily suggest themselves to skilled leatherfinishers, and are included in the invention.

The invention will be described in greater detail by the followingspecific examples. It should be understood, however, that these examplesare given primarily by way of illustration, and that the invention inits broader aspects is not limited thereto.

Example 1 parts of vegetable tanned calk skins are fatliquored in arotating drum using an emulsion of 2-7% of jojoba seed oil in IOU-150%of water, all based on the weight of the skins.

The fatliquoring emulsion may be prepared by stirring the jojoba seedoil into a solution of 1-3% of castile soap in 10-20% of water, based onthe weight of the skins, whereby a creamy white emulsion is produced.The neutralized and washed skins are put into a rotary drum togetherwith 80-130% of their weight of water and the emulsion is added, afterwhich rotation of the drum is started.

Additional emulsifying agents such as egg yolk, lecithin, sulfonatedcastor oil or sulfonated jojoba seed oil may be used in preparing theaqueous emulsion of jojoba seed oil instead of or in addition to thecastile soap if desired. Alternatively the soap may be formed in situ bydissolving oleic acid in the raw jojoba seed oil and pouring the mixturewith agitation into a water solution of sodium hydroxide. In eithercase, the heavy emulsion which is formed may be used as a stock solutionfor addition in relatively small quantitles to the fatliquoring drumwhich contains the hides or skins together with additional water.

Upon rotation of the fatliquoring drum for 30-45 minutes with emulsionsof raw jojoba seed oil prepared in the above manner, a well lubricatedleather is obtained. The emulsion exhausts well and there is no evidenceof greasiness or fat stains on the surface of the leather.

Example 2 parts of jojoba seed oil were cooled to 14 C. and 27.5 partsof concentrated sulfuric acid were slowly added with continuousagitation, the temperature of the mixture being maintained below 30 C.at all times. When the reaction was complete the sulfonation mix waspoured into an excess of 20% sodium hydroxide at temperatures of 40-80C. and the brine was allowed to separate from the oil. The brine wasdrawn oil? and the sulfonated oil was finished by adding a small amountof a dilute sodium hydroxide solution. A light, pale straw colored andpractically odorless oil was obtained.

For purposes of comparison 400 parts of 45 natural Winter sperm oil weresulfonated with 100 parts of concentrated sulfuric acid at 11-24 C. bythe same procedure. The resulting oil was much darker in color than wasthe sulfonated jojoba seed oil and its fishy odor still persisted aftersulfonation.

Chrome tanned amritsars of a weight suitable for glove leather were wellwashed for 20 minutes at 40-50 C. in two rotating fatliquoring drums.After the skins were washed, the drums were drained and charged with ofwater based on the weight of the skins. 10% of the sulfonated jojobaseed oil, also based on the weight of the skins, was dissolved inseveral times its weight of water and added to one of the drums. 10% ofthe sulfonated sperm oil in the form of a similar aqueous solution wasadded to the other drum.

The drums were rotated for 30 minutes at about 50 0., after which theskins were removed and dried at room temperatures. The skins were thenbroken over a dull knife and examined.

It was found that the skin lubricated with sulfonated jojoba seed oilwas much softer and more glossy than the skin treated with sulfonatedsperm oil. Its light color was unimpaired, and there was noobjectionable odor. Both skins showed equally good properties as tostretch or "let-cu and both were entirely free from fat stain.

What I claim is:

1. A method of lubricating skins and leather which comprisesimpregnating them with a lu- CERTIFICATE or Patent No 2,176,L;5h.

bricating composition containing a lubricant selected from the groupconsisting of jojoba seed lubricant comprising jojoba seed oil.

2. A method of stufling skins and leather which comprises impregnatingthem with a non-aqueous lubricant comprising jojoba seed oil.

3. A method of fatliquoring skins and leather which comprises applyingthereto an aqueous emulsion containing sulfonated jojoba seed oil.

JOSEPH G. NIEDERCORN.

CORRECTION October 1'? 179 JOSEPH GEORGE NIEDERCORN. It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction as follows: Page 2, sec-- 0ndcolumn, line 6, for the word "calk" read calf; page 3,

second column,

line 5, claim 1, for "lubricant comprising read oil and sulfonated; and

that the said Letters Patent should be read with this correction the rein that the same may conform to the record of the case in the PatentOffice.

Signed and sealed this lhth day of November, A. D. 1959.

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

It was found that the skin lubricated with sulfonated jojoba seed oilwas much softer and more glossy than the skin treated with sulfonatedsperm oil. Its light color was unimpaired, and there was noobjectionable odor. Both skins showed equally good properties as tostretch or "let-cu and both were entirely free from fat stain.

What I claim is:

1. A method of lubricating skins and leather which comprisesimpregnating them with a lu- CERTIFICATE or Patent No 2,176,L;5h.

bricating composition containing a lubricant selected from the groupconsisting of jojoba seed lubricant comprising jojoba seed oil.

2. A method of stufling skins and leather which comprises impregnatingthem with a non-aqueous lubricant comprising jojoba seed oil.

3. A method of fatliquoring skins and leather which comprises applyingthereto an aqueous emulsion containing sulfonated jojoba seed oil.

JOSEPH G. NIEDERCORN.

CORRECTION October 1'? 179 JOSEPH GEORGE NIEDERCORN. It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction as follows: Page 2, sec-- 0ndcolumn, line 6, for the word "calk" read calf; page 3,

second column,

line 5, claim 1, for "lubricant comprising read oil and sulfonated; and

that the said Letters Patent should be read with this correction the rein that the same may conform to the record of the case in the PatentOffice.

Signed and sealed this lhth day of November, A. D. 1959.

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

